Species of Rhodococcus Depict Evolutionary Transition

Rhodococcus is a genus of Gram-positive bacteria closely related to Mycobacterium and Corynebacterium. These flourish in a broad range of environments, including soil, water, eukaryotic cells.

While some of its species are pathogenic i.e. they deform tissues in plants, the others are benign i.e. they are beneficial and stimulate growth. Recently, a research was conducted at the Oregon State University (OSU) to recognise species of Rhodococcus that transition between beneficial and pathogenic. The researchers made use of genome sequencing for this identification. The research found that this transition between good and bad takes place with the help of DNA molecules known as Plasmids. A Plasmid is a DNA molecule which is maintained separately from the chromosome of bacteria. The growth stimulated by the good strains of the bacteria are often confused as a disease symptom. The transition of Rhodococcus can give rise to new lineages of pathogenic Rhodococcusin in nurseries and other environments. In order to help the nurseries differentiate between the good and bad species of the bacteria, Skylar Fuller, who secured a master's degree in molecular, cellular biology at OSU, has developed molecular tools to work with commercially available kits. Earlier in 2014, a researcher examined the cause of odd symptoms in pistachio trees. He first assumed that Rhodococcus was the cause but later concluded that the strains of bacteria cultured from pistachio were non-pathogenic. Hence, it can be established that beneficial strains in Rhodococcus that stimulate growth are usually misinterpreted as disease symptoms.